Archive

Apr. 24, 2013 — Researchers have identified a burst of high-energy radiation known as ‘dark lightning” immediately preceding a flash of ordinary lightning. The new finding provides observational evidence that the two phenomena are connected, although the exact nature of the relationship between ordinary bright lightning and the dark variety is still unclear, the scientists said.

Three images, left to right, of the same thundercloud depict a less-than-10-milliseconds-long sequence of events: (left) formation within the cloud of a small channel, or ‘leader,’ of electrical conductivity (yellow line) with weak emission of radio signals (ripples), to (middle) a burst of both dark lightning (pink) and radio waves (larger ripples), to (right) a discharge of bright lightning and more radio waves. (Credit: Studio Gohde)

“Our results indicate that both these phenomena, dark and bright lightning, are intrinsic processes in the discharge of lightning,” said Nikolai Østgaard, who is a space scientist at the University of Bergen in Norway and led the research team.

He and his collaborators describe their findings in an article recently accepted in Geophysical Research Letters — a journal of the American Geophysical Union.

Dark lightning is a burst of gamma rays produced during thunderstorms by extremely fast moving electrons colliding with air molecules. Researchers refer to such a burst as a terrestrial gamma ray flash.

NASA’s Mars rover Curiosity paused its work over the weekend and is chilling in safe mode on Mars, while engineers on Earth try to resolve a computer glitch. The rover switched to a backup computer, but operations are on hiatus while NASA engineers work on the problem.

Last week, engineers noticed a glitch in the flash memory on one of the rover’s two computers. Curiosity had normal communications with Earth on Wednesday, Feb. 27, but like an annoying Facebook friend, it updated its status yet included no actual information. In the status update, engineers learned the rover did not go to sleep when planned, and when they started diagnosing the problem, they realized the main A-side computer had some corrupted files.

Feb. 28, 2013 — NASA’s Van Allen Probes mission has discovered a previously unknown third radiation belt around Earth, revealing the existence of unexpected structures and processes within these hazardous regions of space.

Two giant swaths of radiation, known as the Van Allen Belts, surrounding Earth were discovered in 1958. In 2012, observations from the Van Allen Probes showed that a third belt can sometimes appear. The radiation is shown here in yellow, with green representing the spaces between the belts. (Credit: NASA/Van Allen Probes/Goddard Space Flight Center)

The belts, named for their discoverer, James Van Allen, are critical regions for modern society, which is dependent on many space-based technologies. The Van Allen belts are affected by solar storms and space weather and can swell dramatically. When this occurs, they can pose dangers to communications and GPS satellites, as well as humans in space.

Feb. 20, 2013 — NASA’s Mars rover Curiosity has relayed new images that confirm it has successfully obtained the first sample ever collected from the interior of a rock on another planet. No rover has ever drilled into a rock beyond Earth and collected a sample from its interior.

First Curiosity Drilling Sample in the Scoop: This image from NASA’s Curiosity rover shows the first sample of powdered rock extracted by the rover’s drill. (Credit: NASA/JPL-Caltech/MSSS)

Transfer of the powdered-rock sample into an open scoop was visible for the first time in images received Wednesday at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

“Seeing the powder from the drill in the scoop allows us to verify for the first time the drill collected a sample as it bore into the rock,” said JPL’s Scott McCloskey, drill systems engineer for Curiosity. “Many of us have been working toward this day for years. Getting final confirmation of successful drilling is incredibly gratifying. For the sampling team, this is the equivalent of the landing team going crazy after the successful touchdown.”

The drill on Curiosity’s robotic arm took in the powder as it bored a 2.5-inch (6.4-centimeter) hole into a target on flat Martian bedrock on Feb. 8. The rover team plans to have Curiosity sieve the sample and deliver portions of it to analytical instruments inside the rover.

Observations made with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope of the disc of gas and cosmic dust around the young star HD 142527, showing vast streams of gas flowing across the gap in the disc. These are the first direct observations of these streams.
CREDIT: ALMA (ESO/NAOJ/NRAO), S. Casassus et al.

Astronomers studying a newborn star have caught a detailed glimpse of planets forming around it, revealing a never-before seen stage of planetary evolution.

Large gas giant planets appear to be clearing a gap in the disk of material surrounding the star, and using gravity to channel material across the gap to the interior, helping the star to grow. Theoretical simulations have predicted such bridges between outer and inner portions of disks surrounding stars, but none have been directly observed until now.